In the installation of wire and cable facilities, both aerial and buried, such as used to provide communications, it is essential to provide access to the wire or cable at certain preselected locations. Such access is required for providing interconnection usually by splices or terminal connections within pedestal enclosures which are subject to weather conditions of varying temperature and humidity as well as precipitation.
In the design of such pedestal enclosures a number of considerations are involved. Basically, the enclosures should be capable of withstanding all weather conditions. They should also prevent insects or small animals from getting inside. Means must be provided to minimize the entry of ground moisture into the functional region of the pedestal. Also, adequate drainage should be provided to prevent accumulation of any water from condensation or water which enters from flooding. Another consideration is flexibility of design for accommodating a wide range of wire and cable sizes.
In the case of pedestal enclosures, gravel is traditionally placed in the base of the pedestal. The gravel is a good moisture barrier and provides excellent drainage. Aside from the inconvenience of the weight and bulk of the material, gravel is not available locally in all geographic areas. In addition, if the gravel is not used or if improper substitutes for gravel are used, ground moisture will enter the enclosure.
It is highly desirable to provide an enclosure which eliminates the need for gravel as a moisture barrier.